Plastic film bags are manufactured and very commonly used for holding and storing various types of items and things ranging from industrial and manufacturing items to edible goods and medical specimens. Such bags are generally made by joining thin plastic film panels so as to form the bag and range in size and holding capacity. Such bags are also typically manufactured having specific structural components and shapes suited for their intended use. One type of plastic film bag which is today commonly used is initially open for placing a product or item therein and is, thereafter, easily selectively closeable. In the event the item placed in the bag includes or contains liquids, it is desirable that the bag and closure seal be leakproof. It is further desirable that the closure seal be generally secure and, after a product has been placed therein and the bag closed, when desired, the bag can be opened for gaining access to the product therein.
One type of selectively closeable and leakproof plastic film bag is shown in U.S. Pat. No. 4,932,791 and U.S. Pat. No. 5,711,751. These patents disclose plastic film bags formed with front and rear plastic film walls joined together so as to form a bag having a bottom, side edges and an opening between the wall top edges. An adhesive strip is provided on the inside surface of one of the walls and extends linearly near the top edges from side edge to side edge. A release liner is provided which extends the full width of the bag from side edge to side edge but is partially notched at its longitudinal ends for creating a shortened longitudinal portion which is placed within the bag between the front and rear walls and over the adhesive strip. The liner shortened longitudinal portion is generally equally spaced between the bag side edges so that the bag is retained open whereat the release liner is located over the adhesive strip while, at each side edge, the adhesive strip is in contact with both the front and rear walls. By pulling the release liner out from between the front and rear walls, the adhesive strip is exposed to the inside surface of the other wall for thereby selectively adhering or attaching together the front and rear walls along the bag opening and closing the bag.
Although these prior art bags are generally suited for their intended purpose, because the release liner shortened longitudinal portion projects into the bag opening and over the linear strip of adhesive, it is quite often difficult to initiate or start the removal of the release liner thereat. Additionally, because the release liner extends to the bag side edges, a special release liner material is required so that, during production of such bags and the simultaneous cutting of the front and rear panels along the side edges and fusing the front and rear panels thereat, the silicone prevents fusing of the release liner to the front and rear walls at the side edges. Further yet, production of such bags is generally difficult because, as the plastic film webs forming the front and rear walls are located against one another and the adhesive strip is placed on the web surface that will become the interior surface of one of these walls, the release liner having previously been notched and having a freely extending shortened longitudinal portion must be placed, not only by properly projecting the shortened longitudinal portion the correct distance into the bag from the top edges but, also, properly locating the release liner notches so as to be aligned with the area whereat the cutting and fusing knife will thereafter cut and fuse the plastic film webs to form the bag side edges.
Accordingly, a need exists for a selectively closeable plastic film bag which is more readily and easily usable when placing product therein and closing the bag, and which can generally more easily, reliably, and inexpensively be manufactured.